1. Field of the Invention
This invention relates to a fleet of lift trucks having lift trucks for walk-behind operation without a stand-on platform and lift trucks for stand-on operation with a stand-on platform, wherein each lift truck of the fleet of lift trucks has a vehicle frame to which a traction drive unit, a steering device, a lifting device, and, optionally, a stand-on platform can be fastened.
2. Technical Considerations
Lift trucks of the types described above, with and without a driver's stand-on platform, are in the product lines of major manufacturers of industrial trucks and are frequently used by the manufacturers in their own production operations. As used herein, the various lift trucks built by a manufacturer with and without a stand-on platform are identified by the general term “fleet of lift trucks.”
In walk-behind operation, the operator walks behind or next to the lift truck and controls the lift truck by means of a steering bar. Lift trucks that are designed exclusively for walk-behind operation are equipped with a steering bar and do not have a stand-on platform for the operator.
Stand-on operation means that during operation of the lift truck, the operator is on the lift truck, for example in a standing position on a stand-on platform. A steering bar or other suitable operating element can be provided to control a lift truck that has a stand-on platform.
Lift trucks that can be used optionally in stand-on operation or walk-behind operation generally have a stand-on platform that folds up and are generally equipped with a steering bar.
The various possible models of the above-mentioned lift trucks of a fleet of lift trucks place different requirements on the vehicle frame of the lift truck. On lift trucks with a stand-on platform for the driver, the weight that is exerted on the stand-on platform must be absorbed by the vehicle frame. Lift trucks that are designed for stand-on operation generally also have a higher maximum speed than walk-behind lift trucks, in which the maximum speed of travel may not exceed walking speed. Consequently, the dynamic load that is exerted on the vehicle frame during travel on stand-on lift trucks is greater than on walk-behind lift trucks. The higher speed of travel of the stand-on lift trucks also requires a more complex design of the drive system and of the chassis of the lift truck.
To meet these different requirements, it has long been conventional to manufacture the different lift trucks in a fleet of lift trucks with different vehicle frames. With regard to manufacturing, however, this approach requires the maintenance of an inventory of a large number and variety of components for the different lift trucks of the fleet of lift trucks.
Therefore, it is an object of the invention to provide a fleet of lift trucks that can be manufactured with a smaller number of different components than conventional lift trucks.